Microstructure and Mechanical Properties Evolution of FB2 Steel Used for 620℃ Steam-turbine During High Temperature Long-term Aging

被引：0
作者：
Tian X. [1 ]
Qin C. [1 ]
Xu H. [2 ]
Li T. [1 ]
Li Y. [1 ]
Yang B. [1 ]
机构：
[1] Xi'an Thermal Power Research Institute Co., Ltd., Xi'an
[2] Xi'an YiTong Thermal Technology Service Co., Ltd., Xi'an
来源：
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | 2021年 / 41卷 / 09期
关键词：
FB2; steel; High temperature aging; Laves phase; M[!sub]23[!/sub]C[!sub]6[!/sub; Microstructure; Strength;
D O I：
10.13334/j.0258-8013.pcsee.201026
中图分类号：
学科分类号：
摘要：
In order to obtain the evolution law of microstructure and mechanical properties of turbine rotor material FB2 steel at high temperatures, FB2 steel was subjected to aging test at 620℃ for simulate service condition. The microstructure and properties of aging samples of FB2 steel were characterized by room temperature tensile test, impact test, hardness test, scanning electron microscope and transmission electron microscope analysis. The results show that during the high temperature aging process, the strength of FB2 steel decreased slowly with time, and the plasticity and impact absorption energy show no significant change. The width of martensite slab of FB2 steel is not obviously roughened, and the dislocation density decreased slightly with time. The M23C6 cabide size was not obviously roughened. The M23C6 cabide size is about 250nm after aged 10000 h. The high strength of FB2 steel is related to a large amount of dispersed M23C6 carbide. In the high temperature aging process, Laves phase was precipitated on the original austenite grain boundary and martensite lath boundary of FB2 steel. After aging 10000 hours, Laves phase size is reached 2.8μm, and growing up slowly by swallowing growth mechanism. This is an important feature of microstructure aging of FB2 steel. The results can provide technical support and basis for the operation supervision and safety assessment of 620℃ high-efficiency ultra-supercritical units. © 2021 Chin. Soc. for Elec. Eng.
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页码：3232 / 3239
页数：7
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